Evonik Operations Gmbh

Daniel Sudhoff

Philipp Roth

Judith Hierold

Hans Joachim Hasselbach

Imad Moussallem

Martin Steurenthaler

Christian Renner

Thorsten Merker

Daniel Fischer

Christian Kaiser

Markus Held

Ulf Bindernagel

The present invention pertains to a method for producing methionine or salts or derivatives thereof from hydrogen cyanide (HCN), the method comprising a step of producing 2-hydroxy-4-(methylthio)butyronitrile (MMP-CN), or a crude product mixture comprising MMP-CN, by contacting a hydrogen cyanide (HCN) process gas mixture prepared according to the Andrussow process from methane, ammonia and oxygen, with 3-methylmercaptopropionaldehyde (MMP), wherein the HCN process gas mixture is obtained from the crude HCN process gas mixture by adjusting the amount of ammonia to between 20% (v/v) and 60% (v/v) of the amount of the ammonia in the crude HCN process gas mixture.

Method for producing methionine

The present invention relates to a method for preparing methionine or methionine salts. In particular, the invention describes the step of preparing 2-hydroxy-4-(methylthio)butyronitrile (MMP-CN) from 3-methylthiopropanal (MMP) and hydrogen cyanide (HCN) in the presence of ammonia by bringing a gaseous mixture comprising HCN and ammonia into contact with MMP.

Method for preparing methionine

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Hanau, Germany

Daniel Sudhoff